1. Field of the Invention:
The invention relates in general to gas-insulated transmission lines and in particular to an inner conductor load bearing roller for a gas insulated transmission line having a corrugated outer conductor.
2. Description of the Prior Art:
Motion occurs between the inner conductor/insulating means assembly and the outer conductor of a gas insulated transmission line both when the transmission line is first assembled at the factory and while it is in service due to temperature differences between the outer and the inner conductors. The temperature changes may be due to changes in the continuous current and in the ambient temperature the gas-insulated transmission line is operating in.
Previous gas-insulated transmission lines utilized a skid contact member located at the end of the insulator and motion occurred between the skid and the tubular outer sheath. The motion between the skid and the outer sheath may produce particles which reduce the voltage withstand ability of the gas-insulated transmission line. In order to eliminate the production of particles, a roller assembly was installed in place of the skids.
A recent development for gas-insulated transmission lines uses corrugated aluminum for the outer conductor or sheath instead of the smooth elongated aluminum type used previously. The roller or skid design of previous gas-insulated transmission lines, when applied to a corrugated outer conductor or sheath, will have the disadvantages that the inner conductor/insulating means assembly will be forced to rise and fall with the corrugations and the force to obtain this axial motion upon assembly or during service will be high.
Accordingly, it would be desirable to have a transport means for the inner conductor/insulating means assembly which retains the advantages of not producing particles and the low force of the previous roller design but is applicable to a corrugated sheath outer conductor without having the disadvantage of radial movement of the inner conductor/insulating means assembly during axial movement of the inner conductor relative to the outer corrugated sheath.